The invention relates to a jig loading system and is primarily concerned with a system which will enable aircraft wing stringers to be positioned at a jig for loading thereon.
Aircraft wing stringers arc commonly supplied to an aircraft manufacturer in a long box, typically up to twenty meters in length. After unpacking the individual stringers and removing a polythene wrapping, the stringers are traditionally laid on trestles and arc then carried individually by hand from the trestle to a jig used for assembling the wing stringers on to a wing structure. The jig is arranged vertically with the wing span extending horizontally. The jig typically extends up to around 2.5 meters above floor level aid each stringer needs to be fitted into a prescribed slot and clamped in position. When all the wing stringers have been fitted into the jig, a wing skin is clamped in position on the jig so as to overlie the stringers in known manner.
As will be appreciated, the aforesaid traditional method of handling the stringers is totally manual and necessitates the availability of several operatives to handle the long stringers. Also, because of the extreme length and slender cross section of the stringers they can easily bend and whip when being carried. The stringers are also difficult to handle when being mounted on the higher parts of the jig in view of their size.
An object of the present invention is provide a jig loading system which will help reduce the problems outlined above and which will support wing stringers more positively at the jig prior to loading.
According to one aspect of the invention there is provided a jig loading system comprising an assembly of elongate members for attachment to a support member so as to hang downwardly in spaced apart positions, each elongate member having a releasable holder thereon, the holders of the assembly being arranged to support an aircraft stringer at spaced apart positions to enable the stringer to be supported at the jig for loading thereon.
With a system in accordance with the invention, the stringer can be supported along its length by the holders thereby reducing significantly the likelihood of unwanted bending or whip in the stringer during loading on to the jig.
Preferably, the holder of each elongate member is loop-like. In such a case the loop may be openable or closeable to enable the stringer to be positioned therein or released therefrom.
In a preferred embodiment, the holder is openable or closeable by means of a releasable spring clip. Preferably, the spring clip can e clipped to a ring or the like to close the holder. The spring clip or the ring is preferably arranged at one end of a length of material which is attached to its elongate member and the ring or spring clip is preferably arranged to provide an anchor which may be mounted on the elongate member to which the length of material is attached. In the preferred embodiment, the releasable spring clip is provided at said one end of the length of material. In such a case, a said ring may form the anchor.
The anchor may be mounted on the elongate member at a position adjacent an attachment point for an adjacent length of material which forms a said further holder on the elongate member.
In a preferred arrangement, each clongate member has a plurality of holders thereon at spaced apart intervals. In such a case, each holder on a said elongate member may overlap an adjacent holder to provide a staggered holder arrangement. That particular configuration provides increased flexibility with respect to the spacing of stringers supported by the holders. Normally, the holders on one of the spaced apart elongate members will be substantially aligned with corresponding holders on an adjacent elongate member.
Preferably, the elongate members are flexible and may conveniently take the form of straps. The flexibility facilitates transfer of stringers to the jig and also allows compact storage.
The moving of the stringers from the trestles to the jig involves repetitive journeys all taking up time and increasing the risk of possible damage. One of the advantages of the present invention is that the jig loading system can be assembled for transport as a package with a stringer in the holders. Where each of the elongate members has a plurality of holders thereon, a plurality of stringers may be positioned in the holders which are assembled as a package. For ease of unpacking, the support member is preferably attachable to the elongate members in the package whereby the assembly of elongate members and stringers can be unpacked by hoisting the support member by suitable means to lift the elongate members and the stringer or stringers thereon into a desired position at the jig. In that way, the stringers can be packed by the stringer manufacturer in such a way that the end user receives the stringers in a form ready for lifting straight up to the jig which is particularly useful from the point of view of jig loading time and ease of handling. If desired, the support member may be attached to the elongate members in the package thereby forming part of the package itself.
According to another aspect of the invention there is provided a method of packaging aircraft wing stringers for subsequent loading on to a jig, the method comprising providing a plurality of elongate flexible support members each of which has thereon a plurality of releasable holders, spacing the elongate members apart, positioning a plurality of stringers in said releasable holders so that the stringers lie alongside each other, forming the assembled elongate members and stringers as a package, transporting the package to a position near a jig, lifting the elongate members so as to unpack the assembly and positioning the stringers at the jig for loading thereon.
The method may include the use of features set out in any of the consistory clauses relating to the first said aspect of the invention.